In an elevator system, there must be a safety system according to safety regulations, by the aid of which safety system the operation of the elevator system can be stopped e.g. as a consequence of a defect or of an operating error. The aforementioned safety system comprises a safety circuit, which comprises safety switches in series, which switches measure the safety of the system. Opening of a safety switch indicates that the safety of the elevator system has been jeopardized. In this case operation of the elevator system is interrupted and the elevator system is brought into a safe state by disconnecting with contactors the power supply from the electricity network to the elevator motor. In addition, the machinery brakes are activated by disconnecting with a contactor the current supply to the electromagnet of a machinery brake.
Contactors, as mechanical components, are unreliable because they only withstand a certain number of current disconnections. The contacts of a contactor might also weld closed if they are overloaded, in which case the ability of the contactor to disconnect the current ceases. A failure of a contactor might consequently result in impaired safety in the elevator system.
As components, contactors are of large size, for which reason devices containing contactors also become large. On the other hand, it is a general aim to utilize built space as efficiently as possible, in which case the disposal of large-sized elevator components containing contactors may cause problems.
Consequently there would be a need to find a solution for reducing the number of contactors in an elevator system without impairing the safety of the elevator system.